JP2002336379A - Golf ball cover-modifying composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a golf ball cover-modifying composition which makes it possible to obtain a gold ball cover having high repulsiveness and scratch resistance by adding and using the reforming composition into a thermoplastic high-polymer material, such as a thermoplastic polyurethane material, in molding the golf ball cover formed by using the thermoplastic high-polymer material. SOLUTION: This golf ball cover-reforming composition consists of an isocyanate mixture prepared by dispersing an isocyanate compound (X) having >=2 isocyanate groups as functional groups in one molecule into a thermoplastic resin (Y) which does not substantially react with the isocyanate and is >=45% in the modulus of elasticity in repulsion.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a composition for modifying a golf ball cover used when molding a golf ball cover using a thermoplastic polymer material, and more particularly, to a main component of a golf ball cover. Is a thermoplastic polymer material capable of substantially reacting with the isocyanate group contained in the composition of the present invention, by being used by adding the composition of the present invention to the thermoplastic polymer material during molding, The present invention relates to a golf ball cover modifying composition that acts as a crosslinking agent for the thermoplastic polymer material.

[0002]

2. Description of the Related Art In recent years, attention has been paid to the use of polyurethane materials as cover materials for golf balls. Polyurethane materials are broadly classified into thermosetting polyurethane materials and thermoplastic polyurethane materials from the viewpoint of a molding method of a molded product. In the former molded product of thermosetting polyurethane material, a urethane prepolymer having an isocyanate terminal group and a liquid material of a curing agent such as a polyol or polyamine are heated and mixed, and the mixture is directly poured into a mold and heated to perform a urethane curing reaction. Can be obtained.

There have been many proposals for golf balls using the above-mentioned thermosetting polyurethane materials. For example, US Pat. Nos. 5,334,673 and 6,117,024.
No. 6,190,268 and the like. As for a method for molding a thermosetting polyurethane material, see, for example, US Pat.
Nos. 3428, 5888437, 5897
Nos. 884 and 5947843.

[0004] Since a molded product of a thermosetting polyurethane material has no plasticity due to heating, it is impossible to recycle raw materials and molded products. In addition, since the molded article of the thermosetting polyurethane material has a long heating and curing step and a long cooling step, and the heating reactivity of the raw materials is high and unstable, it is very difficult to control the molding time. The productivity when applied to a special molded product such as a golf ball cover (a molded product that covers the periphery of a core material) is not efficient.

On the other hand, the latter molded article of thermoplastic polyurethane material is not obtained by directly reacting the raw materials to obtain a molded article, but by using a slightly different raw material and manufacturing method from the above-mentioned molded article of thermosetting polyurethane material. The linear polyurethane material synthesized by use is used for molding. Such a polyurethane material has thermoplasticity, and the thermoplasticized polyurethane material has a property of solidifying when cooled. Therefore, such a polyurethane material can be molded using an injection molding machine. Injection molding of a thermoplastic polyurethane material is most suitable as a molding method of a golf ball cover because the molding time is very short as compared with the molding time of a thermosetting urethane material and is suitable for precision molding. In addition, the thermoplastic polyurethane material is recyclable and is environmentally friendly. U.S. Pat. Nos. 3,395,109 and 42,484
Japanese Patent Nos. 32442 and 4442282 propose golf balls using a thermoplastic polyurethane material.

However, a golf ball cover using a conventional thermoplastic polyurethane material does not satisfy all of the feel, controllability, resilience, and abrasion resistance when hit with an iron.

On the other hand, Japanese Patent Application Laid-Open No. 9-271538 discloses a golf ball cover using a highly resilient thermoplastic polyurethane material. However, this golf ball cover did not have sufficient scratch resistance when hit with an iron.

Japanese Patent Application Laid-Open No. H11-178949 describes a golf ball cover containing a reaction product of a thermoplastic polyurethane material and an isocyanate compound as a main component and having relatively good scratch resistance when hit with an iron. ing. In this cover, diisocyanate as an additive,
An isocyanate compound such as a blocked isocyanate dimer is added to a thermoplastic polyurethane material.
As an addition method, it is made to react at the time of molding by adding at the time of hot melt mixing using an extruder or at the time of injection molding.

However, in the molding of the cover disclosed in JP-A-11-178949, it is difficult to handle the isocyanate compound due to deactivation by moisture, and it is difficult to obtain a stable reaction product. Further, the blocked isocyanate which is resistant to moisture absorption had a strong odor of the blocking agent when dissociated by heat, and was not suitable for molding the cover.
Furthermore, when the isocyanate compound is in the form of a powder or a solution, it is difficult to control the amount of the isocyanate compound added to the thermoplastic polyurethane material, and it is difficult to control the physical properties of the cover. Further, a slip phenomenon in a molding machine occurs due to a difference in melting point and a difference in melt viscosity between the thermoplastic polyurethane material and the isocyanate compound, so that sufficient kneading may not be performed. In the technology described in the above publication, the influence of moisture and the control of the additive amount in the cover material become insufficient due to the above reasons, and as a result, a golf ball which can sufficiently satisfy the effect of improving the scratch resistance. I couldn't get a ball cover.

Further, the preferred thermoplastic polyurethane material described in JP-A-11-178949 is based on an aliphatic isocyanate, and this thermoplastic polyurethane material has a low reactivity with isocyanate. It is very large and it is difficult to control the reaction, so it is easy to gel before using it for injection molding, and it is not possible to ensure sufficient plasticity.It is also possible that gelation may occur during molding. Had a lot of problems, such as a problem that the reproduction could not be performed. And it was difficult to put it to practical use because of the above problems.

Japanese Patent Publication No. 58-2063 (US Pat. No. 4,347,338) discloses that a compound having two or more isocyanate groups is mixed with a thermoplastic resin which does not react with the isocyanate group, and the resulting mixture is used as a mixture. A method for producing a thermosetting polyurethane molded product which is blended with a thermoplastic polyurethane material and molded by a molding machine is described. However, the technique described in the above publication is intended only to improve the solvent property and continuous repeated abrasion.
The use of the molding material as a cover material for golf balls is not disclosed. Golf ball cover materials include rebound, flight distance, spin, controllability,
Materials satisfying various characteristics required for golf balls such as hit feeling, scratch resistance, cut resistance, and discoloration resistance are demanded.
In addition, it is desired to appropriately combine those materials.

[0012]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned circumstances, and has been described in connection with molding a golf ball cover using a thermoplastic polymer material such as a thermoplastic polyurethane material. Used in addition to a molecular material to act as a cross-linking agent for the thermoplastic polymer material, thereby providing a golf ball cover having high resilience and excellent scratch resistance. It is intended to provide a composition.

[0013]

In order to achieve the above object, the present invention provides a composition for modifying a golf ball cover shown in the following (1) to (4).

(1) An isocyanate compound (X) having two or more isocyanate groups as a functional group in one molecule
A isocyanate mixture which is substantially non-reactive with isocyanate and is dispersed in a thermoplastic resin (Y) having a rebound resilience of 45% or more.

(2) When the isocyanate compound (X) is 4,
4'-diphenylmethane diisocyanate (1)
A composition for modifying a golf ball cover.

(3) The golf ball cover modifying composition according to (1) or (2), wherein the thermoplastic resin (Y) is a polyester elastomer.

(4) The mixing ratio of the thermoplastic resin (Y): isocyanate compound (X) is 100: 5 to 10 by mass.
The golf ball cover modifying composition according to any one of claims 1 to 3, wherein the composition is 0: 100.

[0018]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in more detail. In the present invention, 2 as a functional group in one molecule
As the isocyanate compound (X) having two or more isocyanate groups, those used in a conventional technique relating to a thermoplastic polyurethane material can be suitably used. For example, 4,4′-diphenylmethane diisocyanate, 2,4-toluene Examples thereof include, but are not limited to, aromatic diisocyanates such as diisocyanate and 2,6-toluene diisocyanate, and aliphatic diisocyanates such as hexamethylene diisocyanate. However, in terms of reactivity and work safety,
4,4'-diphenylmethane diisocyanate is optimal.

As the thermoplastic resin (Y) which does not substantially react with the isocyanate, a resin having low water absorption and excellent compatibility with a thermoplastic polymer material to be cross-linked (described later) is preferable. The properties that the thermoplastic resin (Y) should have are excellent compatibility with the thermoplastic polymer material to be crosslinked, high rebound resilience and high strength.
As for the rebound resilience, the rebound resilience according to JIS-K7311 is 45% or more, particularly 50% or more, and more preferably 55% or more.
% Is preferable. If the rebound resilience is lower than 45%, the resilience of the molded product will be significantly reduced.
Therefore, the thermoplastic resin (Y) suitable for the thermoplastic polymer material to be cross-linked may be selected in consideration of the above points. For example, when a thermoplastic urethane material is used as the thermoplastic polymer material, the thermoplastic resin (Y) may be a polyester such as an ether / ester block copolymer or an ester / ester block copolymer from the above-described points. Elastomers are particularly preferred.

The mixing ratio of the thermoplastic resin (Y) to the isocyanate compound (X) in the composition of the present invention is 100: 5 to 100: 100, especially 100: 10 to 100% by mass.
Preferably it is 100: 40. If the compounding amount of the isocyanate compound (X) is too small relative to the thermoplastic resin (Y), when the golf ball modifying composition of the present invention is added to the thermoplastic polymer material in a specific amount, the effect of (X) is more than (Y). The effect of improving the abrasion resistance and cut resistance cannot be sufficiently obtained because the physical properties of the composition greatly affect the physical properties of the golf ball. Since the influence of the physical properties of (Y) is reduced, the effect of improving the resilience may not be sufficiently obtained.

The composition of the present invention is prepared by, for example, blending an isocyanate compound (X) with a thermoplastic resin (Y), kneading the mixture thoroughly with a mixing roll or a Banbury mixer at a temperature of 130 to 250 ° C., and pelletizing the mixture. Alternatively, it can be obtained by crushing after cooling. At this time,
If water is mixed during kneading, most of the isocyanate is deactivated due to the reaction between the water and the isocyanate, and the original cross-linking agent effect cannot be obtained.

The thermoplastic polymer material to which the composition of the present invention is added at the time of molding a golf ball cover, that is, a thermoplastic polymer material which can be substantially reacted with an isocyanate which can be used in combination with the composition of the present invention, includes: Although not particularly limited, a thermoplastic polymer material having a polar group such as an amino group, a hydroxyl group, a urea group, or a urethane group is preferable. For example, as a thermoplastic polymer material, a thermoplastic polyurethane material, a polyamide elastomer, a modified polyester elastomer, a resin having a polar group such as an ionomer resin, an elastomer, or the like, which causes a crosslinking reaction with isocyanate, is used as a golf ball cover material. Any one that can be used may be used. Particularly preferred among these are thermoplastic polyurethane materials in various respects such as resilience, flexibility, and reactivity with isocyanates.

The structure of the thermoplastic polyurethane material comprises a soft segment composed of a high molecular polyol (polymeric glycol), a chain extender constituting a hard segment and a diisocyanate. Here, as the polymer polyol as a raw material, any of those conventionally used in the technology related to thermoplastic polyurethane materials can be used, and there is no particular limitation, and there are polyester-based and polyether-based. A polyether-based material is more preferable than a polyester-based material because a thermoplastic polyurethane material having a high elastic modulus and excellent low-temperature characteristics can be synthesized. Examples of the polyether polyol include polytetramethylene glycol, polypropylene glycol, and the like, and polytetramethylene glycol is particularly preferable in terms of resilience and low-temperature characteristics. Further, the average molecular weight of the high molecular polyol is preferably 1,000 to 5,000, and particularly preferably 2,000 to 4,000 in order to synthesize a thermoplastic polyurethane material having high rebound resilience.

As the chain extender, those used in the art relating to conventional thermoplastic polyurethane materials can be suitably used. For example, 1,4-butylene glycol, 1,2-ethylene glycol, 1,3-butane Diol, 1,6-hexanediol, 2,2-dimethyl-
Examples include, but are not limited to, 1,3-propanediol. The average molecular weight of these chain extenders is preferably from 20 to 15,000.

As the diisocyanate, those used in the art relating to conventional thermoplastic polyurethane materials can be suitably used. For example, 4,4'-diphenylmethane diisocyanate, 2,4-toluene diisocyanate, 2,6-toluene diisocyanate And aliphatic diisocyanates such as hexamethylene diisocyanate, but are not limited thereto. However, it is difficult to control the crosslinking reaction during injection molding depending on the type of isocyanate. In the present invention, 4,4′-diphenylmethane diisocyanate, which is an aromatic diisocyanate, is most preferable in view of the stability of the reactivity with the composition of the present invention described above.

As the thermoplastic polyurethane material composed of the above-mentioned materials, commercially available products can be suitably used. For example, Pandex T-8290, T-8295, T8260 manufactured by DC Bayer Polymer, and Dainichi Seika Rezamine 2593, 2597 manufactured by Kogyo Co., Ltd., and the like.

The mixing ratio of the thermoplastic polymer material capable of substantially reacting with isocyanate such as a thermoplastic polyurethane material: the composition of the present invention is 100: 1 to 100: 1 by mass.
00, especially 100: 5 to 100: 50, especially 100:
It is preferably 10 to 100: 30. If the amount of the composition of the present invention with respect to the thermoplastic polymer material is too small, the crosslinking effect is not sufficiently exhibited, and if it is too large, unreacted isocyanate causes a coloring phenomenon in the molded product, which is not preferable.

In the present invention, other thermoplastic polymer materials can be added to the cover molding material in addition to the above-mentioned components. As such other components, for example, a polyester elastomer, a polyamide elastomer, an ionomer resin, a styrene block elastomer, polyethylene, a nylon resin and the like can be blended. In this case, the blending amount of the thermoplastic polymer material other than the thermoplastic polymer material capable of substantially reacting with the isocyanate such as the thermoplastic polyurethane material described above is substantially equal to the isocyanate such as the thermoplastic polyurethane material as an essential component. 0 to 1 with respect to 100 parts by mass of the thermoplastic polymer material capable of reacting
00 parts by mass, preferably 10 to 75 parts by mass, more preferably 10 to 50 parts by mass, and is appropriately selected according to adjustment of the hardness of the cover material, improvement of resilience, improvement of fluidity, improvement of adhesion, and the like. Is done. In addition, cover molding materials include
Various additives can be blended as required, and for example, pigments, dispersants, antioxidants, light stabilizers, ultraviolet absorbers, mold release agents, and the like can be appropriately blended.

When the composition of the present invention is used, for example,
The composition of the present invention is added to a thermoplastic polymer material capable of substantially reacting with isocyanate such as a thermoplastic polyurethane material and dry-mixed, and the mixture is used to form a cover around the core by an injection molding machine. be able to. The molding temperature varies depending on the type of the thermoplastic polymer material used, but is usually in the range of 120 to 300 ° C.

The reaction mode and cross-linking mode of the golf ball cover obtained as described above include, for example, when the thermoplastic polymer material is a thermoplastic polyurethane material, an isocyanate group is added to the remaining OH group of the thermoplastic polyurethane material. Reacts to form a urethane bond, or an addition reaction of an isocyanate group to a urethane group of the thermoplastic polyurethane material occurs to form an allophanate or buret crosslinked form. In this case, the crosslinking reaction does not sufficiently proceed immediately after injection molding of the cover molding material, but the crosslinking reaction proceeds by performing annealing after molding,
The property useful as a golf ball cover is maintained. Annealing means that the cover is aged by heating at a certain temperature for a certain time, or is aged at room temperature for a certain period.

In the golf ball using the composition of the present invention, the surface hardness of the cover material is 40 to 80, particularly 43 to 6 in durometer D type hardness according to JIS-K6253.
It is suitably 0, more preferably 45-55. If the surface hardness of the cover material is too low, back spin is applied too much with an iron shot, and controllability deteriorates. On the other hand, if the surface hardness of the cover material is too high, the back spin performance on iron shots becomes insufficient, the controllability is reduced, and the hit feeling is deteriorated.

Further, in the golf ball using the composition of the present invention, the cover material has a rebound resilience according to JIS-K7311 of 45% or more, particularly 45 to 85%, particularly 50 to 80%, and more preferably 50 to 80%. Suitably, it is ６０60%. Since a thermoplastic polymer material capable of substantially reacting with an isocyanate, for example, a thermoplastic polyurethane material, is not originally a material having such a high resilience, it is preferable to strictly select the rebound resilience. If the rebound resilience of the cover material is too low, the flight distance of the golf ball is greatly reduced. If the rebound resilience of the cover material is too high, 100
Shots and puttings that require control within the yard can cause the initial speed to be too high and not fit the golfer's feeling.

The core used in the golf ball using the composition of the present invention is not particularly limited, and any core usually used can be used. For example, a solid core for a two-piece ball, a plurality of vulcanized rubber layers Various cores such as a solid core having a rubber core, a solid core having a plurality of resin layers, and a wound core having a thread rubber layer can be used. There is no limitation on the outer diameter, mass, hardness, material, etc. of the core. Further, the thickness of the cover of the golf ball using the composition of the present invention is preferably in the range of 0.1 to 5.0 mm. Note that the cover is not limited to a single layer, and may be formed in a multilayer structure.

A golf ball using the composition of the present invention
Formed in diameter and mass according to the Rules of Golf, usually
It is formed with a diameter of not less than 42.67 mm and a weight of not more than 45.93 g, preferably having a diameter of 42.67 to 42.9 mm, and having a deformation of 2.0 to 4 balls under a load of 980 N (100 kg). 2.0 mm, especially 2.2 to 3.8
mm is appropriate.

[0035]

EXAMPLES The present invention will be specifically described below with reference to examples and comparative examples, but the present invention is not limited to the following examples.

(Examples, Comparative Examples) Composition 1 for modifying a golf ball cover of the present invention having the composition (unit: parts by mass) shown in Table 1
~ 3 were prepared. As the isocyanate compound (X), 4,4'-diphenylmethane diisocyanate (Millionate MT-F manufactured by Nippon Polyurethane Industry Co., Ltd.), and as the base resin, an ether ester block copolymer (thermoplastic Resin (Y), rebound resilience 70%), soft vinyl chloride resin pellets previously dried to remove moisture (plasticizer DOP50PHR, rebound resilience 35%), polystyrene resin previously dried to remove moisture (rebound resilience 35%) ) Was used for each. After thoroughly mixing the materials with a tumbler, the resulting mixture was subjected to a vented extruder and extruded at a temperature of 120 to 200 ° C to obtain a strand, which was cooled and pelletized.

[0037]

[Table 1]

Core composition polybutadiene rubber 100 parts by mass Zinc acrylate 21.5 parts by mass Zinc oxide 12 parts by mass Dicumyl peroxide 1 part by mass

After kneading the core material having the above composition, 155
38.5 m in diameter by vulcanization molding at 20 ° C for 20 minutes
m was obtained for a two-piece solid golf ball. In addition, BR01 manufactured by Nippon Synthetic Rubber Co., Ltd. was used as the polybutadiene rubber. The specific gravity of the obtained core was 1.
The amount of deformation when a load of 07, 980 N (100 kg) was applied was 3.4 mm, and the initial velocity measured according to the USGA (R & A) measurement method was 78.1 m / s.

Further, cover materials (unit: parts by mass) shown in Tables 2 and 3 were kneaded at a kneading temperature of 190 ° C. by a screw type twin screw extruder to obtain cover molding materials. Table 2
The following components were used as the components in Table 3. Polyurethane 1 (thermoplastic polyurethane material) Pandex T8290: MDI-PTMG type thermoplastic polyurethane material manufactured by DIC Bayer Polymer Co., Ltd., surface hardness JIS-A93, rebound resilience 52
%. -Polyurethane 2 (thermoplastic polyurethane material) Pandex T8295: MDI-PTMG type thermoplastic polyurethane material manufactured by DIC Bayer Polymer Co., Ltd., surface hardness JIS-A97, rebound resilience 44
%. Polyurethane 3 (thermoplastic polyurethane material) Pandex T8260: MDI-PTMG type thermoplastic polyurethane material manufactured by DC Bayer Polymer Co., Ltd., durometer D type surface hardness 56, rebound resilience 45%.

Next, the solid core is placed in an injection molding die, and a dry blend of the cover material and the cover material is formed around the core by injection molding to provide a cover having a 2.1 mm thick cover. Example and Comparative Example two-piece golf balls were obtained. After leaving the obtained golf ball at room temperature for one week, the ball characteristics were evaluated. The evaluation method is as follows. Further, the physical properties of the cover were measured after a sheet having a thickness of 2 mm obtained by injection molding was left at room temperature for one week. The results are shown in Tables 2 and 3.

(Cover Physical Properties) Surface Hardness A durometer D-type hardness according to JIS-K6253 was measured. The rebound resilience was measured according to JIS-K7311.

[0043] was measured deformation amount when added (ball properties) Hardness 980 N (100 kg) load. The initial speed was measured in accordance with the USGA (R & A) measurement method. Using a flying distance swing robot machine, the club uses the No. 1 wood (driver) and a head speed of 45 m / s.
The total flight distance when hitting was measured.

While keeping the iron abrasion-resistant balls at 23 ° C., 13 ° C., and 0 ° C., respectively, the club was hit with a pitching wedge at a head speed of 33 m / s using a swing robot machine. The impact damage was visually evaluated according to the following criteria. 5 points: No scratches or almost no scratches. 4 points: Some scratches are observed, but they are hardly noticeable. 3 points: The surface is slightly fuzzy. 2 points: The surface is fuzzy or dimples are missing. 1: The dimple has been completely removed.

[0045]

[Table 2]

[0046]

[Table 3]

As is clear from the results shown in Tables 2 and 3, the golf balls of the Examples all contained the composition of the present invention, so that they had high resilience and exhibited good flight performance. It was also found that the abrasion resistance at the time of hitting the iron was very excellent. In contrast, none of the golf balls of Comparative Examples contained the composition of the present invention, so that the resilience was poor and the abrasion resistance when hit with an iron was not satisfactory.

[0048]

As described above, the composition for modifying a golf ball cover according to the present invention can be used for molding a golf ball cover using a thermoplastic polymer material such as a thermoplastic polyurethane material. A golf ball cover having high resilience and excellent abrasion resistance can be obtained by adding it to a polymer material.

Claims (4)

[Claims] 1. An isocyanate compound (X) having two or more isocyanate groups as a functional group in one molecule is not substantially reacted with isocyanate and has a rebound resilience of 4 or less.
A golf ball cover modifying composition comprising an isocyanate mixture dispersed in a thermoplastic resin (Y) having a content of 5% or more. 2. An isocyanate compound (X) comprising 4,4 ′
The composition for modifying a golf ball cover according to claim 1, which is diphenylmethane diisocyanate. 3. The golf ball cover modifying composition according to claim 1, wherein the thermoplastic resin (Y) is a polyester elastomer. 4. The mixing ratio of the thermoplastic resin (Y): isocyanate compound (X) is 100: 5 to 100: 1 by mass.
The golf ball cover modifying composition according to claim 1, wherein the composition is 00.